Convertible apparatus for heat treating materials

Abstract

A heating system for heat treating a continuous sheet-like material includes an input end and an output end and a path defined therebetween that extends between the input and output ends for the material to be treated. At least one section of the heating system includes an upper movable heater and a lower stationary heater disposed on confrontingly opposite sides of the material path. A heater lifter is connected to the movable upper heater for operatively displacing the upper heater between a first position for imparting a curing type of heat treatment and a second position for imparting an annealing type of heat treatment to the continuous sheet material as it is advanced through the heating system.

We claim: 
     
       1. A convertible heating system for use in a process line for heat treating a continuous sheet material as the continuous sheet material is advanced along the heating system, wherein the process line includes an entry section for supplying untreated continuous sheet material to the convertible heating system and an exit section for receiving the treated continuous sheet material from the convertible heating system, said convertible heating system comprising: a housing having an input end for receiving the continuous sheet material to be heat treated and an output end and defining a path along which the material is operatively advanced through the housing from the input end to the output end, said housing, enclosing a plurality of heating sections disposed serially along the path;   a convertible section of said plural heating sections comprising confrontingly opposed first and second heaters disposed on respectively opposite sides of said path for directing heated air from said heaters toward opposed faces of the continuous sheet material as the continuous sheet material is advanced along the path in said housing, said second heater being positionally fixed in said housing and said first heater being movable substantially transverse to said path between a first position predeterminately spaced from said second heater for applying a first heat treatment to the continuous sheet material and a second position more remote from the second heater than said predeterminate spacing of said first position for applying a second heat treatment to the continuous sheet material; and   a heater lifting device connected to said first heater and selectively operable to move said first heater between said first and second positions of the first heater for converting said heating system between first and second heat treatment configurations for applying said first and second heat treatments to the continuous sheet material;   said second heater comprising means for directing a stream of heated air substantially upwardly onto one of the opposed faces of the continuous sheet material so as to support the continuous sheet material on the stream of heated air in a substantially horizontal orientation through said convertible section in said first position of the first heater for applying said first heat treatment to the continuous sheet material, and for directing the stream of heated air substantially upwardly onto the one of the opposed faces of the continuous sheet material without supporting the continuous sheet material on the stream of heated air and thereby permitting the sheet material to assume a catenary sag through said adjustable section in said second position of the first heater for applying said second heat treatment to the unsupported continuous sheet material.   
     
     
       2. The convertible heating system of claim 1, wherein said adjustable section comprises a first one of said serially-disposed plural sections located immediately adjacent said entrance end of the convertible heating system. 
     
     
       3. The convertible heating system of claim 1, wherein said second heater comprises a plurality of floatation nozzles configured for directing the heated air from the second heater upwardly toward the continuous sheet material so as to support the continuous sheet material on the heated air in said substantially horizontal orientation in said first position of the first heater. 
     
     
       4. The convertible heating system of claim 1, wherein said first heat treatment comprises one of annealing, tempering, preheating and normalizing, and said second heat treatment comprises curing. 
     
     
       5. The convertible heating system of claim 1, wherein said input end of the housing is configured for introducing the continuous sheet material into the housing at a first distance above said second heater in said first position of said first heater for applying said first heat treatment to the continuous sheet material as the sheet material is advanced along said path, and at a second distance above said second heater and greater than said first distance for applying said second heat treatment to the continuous sheet material as the sheet material is advanced along said path, said second distance being sufficient to avoid contact of the second heater with the continuous sheet material in said catenary sag. 
     
     
       6. The convertible heating system of claim 1, wherein said first heater comprises a plurality of movable heater units, and wherein said heater lifting device is connected to said plural heater units for operatively displacing each said heater unit to a distinct second position so that each said heater unit is differently spaced from the second heater in said second position of the first heater for applying said first heat treatment to the continuous sheet material in said catenary sag. 
     
     
       7. The convertible heating system of claim 6, wherein said distinct second positions of said heater units are selected so that said heater units are spaced from said second heater so as to substantially track the catenary sag of the continuous sheet material. 
     
     
       8. The convertible heating system of claim 5, wherein said first heater comprises a plurality of movable heater units, and wherein said heater lifting device is connected to said plural heater units for operatively displacing each said heater unit to a distinct second position so that each said heater unit is differently spaced from the second heater in said second position of the first heater for applying said first heat treatment to the continuous sheet material in said catenary sag. 
     
     
       9. The convertible heating system of claim 8, wherein said distinct second positions of said heater units are selected so that said heater units are spaced from said second heater so as to substantially track the catenary sag of the continuous sheet material. 
     
     
       10. The convertible heating system of claim 1, further comprising a controller having an output connected to said heater lifting device and a user-operable input device for user selection of one of the first and second heat treatment configurations, said controller output being responsive to said user-operable input device for causing said heater lifting device to move said first heater between said first and second positions in response to said controller output. 
     
     
       11. The convertible heating system of claim 10, further comprising a temperature detector located in said housing proximate an output end of one of said plural heating sections for operatively detecting a temperature of the continuous sheet material proximate the output end of said one of the plural heating sections, and connected to said controller for use by said controller in causing said heater lifting device to adjust at least one of the first and second positions of the first heater for effecting a predetermined heat treatment of the continuous sheet material in said housing. 
     
     
       12. The convertible heating system of claim 11, wherein said user-operable input device comprises a temperature selection device operable for user selection of a desired temperature of the continuous sheet material at the output end of said one of the plural heating sections, and wherein said controller is operable for automatically adjusting a heat output applied to the continuous sheet material in said one of the plural heating sections in response to the user-selected desired temperature and the temperature detected by said temperature detector. 
     
     
       13. The convertible heating system of claim 1, wherein said housing further comprises a barrier disposed separatingly between adjacent ones of said plural heating sections for enabling maintenance of desired temperature differentials between the adjacent heating sections separated by said barrier. 
     
     
       14. The convertible heating system of claim 1, wherein the process line further includes a coater between said entry section and said convertible heating system for applying a coating to the continuous sheet material before the sheet material enters the heating system for application of the second heat treatment to the continuous sheet material in said housing, and wherein said input end of the housing is configured for introducing the continuous sheet material into the housing at a first distance above said second heater in said first position of said first heater and when the continuous sheet material is diverted from the coater for applying said first heat treatment to the continuous sheet material as the sheet material is advanced along said path, and said input end of the housing is configured for introducing the continuous sheet material into the housing from the coater at a second distance above said second heater and greater than said first distance for applying said second heat treatment to the continuous sheet material as the sheet material is advanced along said path, said second distance being sufficient to avoid contact of the second heater with the continuous sheet material in said catenary sag. 
     
     
       15. The convertible heating system of claim 1, wherein said plural heating sections further comprise a fixed heating section serially following said convertible section and having a set of upper and lower heaters confrontingly opposed on respectively opposite sides of said path for directing heated air from said upper and lower heaters toward the opposed faces of the continuous sheet material as the continuous sheet material is advanced along the path in said fixed heating section, and a cooling section following said fixed heating section for cooling the continuous sheet material as the continuous sheet material is advanced along the path in said cooling section by directing air toward the opposed faces of the continuous sheet material in said cooling section. 
     
     
       16. The convertible heating system of claim 15, wherein predeterminately heated air is directed toward the opposed faces of the continuous sheet material in said cooling section. 
     
     
       17. The convertible heating system of claim 15, wherein unheated ambient air is directed toward the opposed faces of the continuous sheet material in said cooling section. 
     
     
       18. The convertible heating system of claim 15, wherein said housing further comprises a barrier disposed separatingly between adjacent ones of said plural heating sections for enabling maintenance of desired temperature differentials between the adjacent heating sections separated by said barrier.